WASHINGTON -- President Obama's health care law is constitutional as a tax - but only a small percentage of Americans will pay more, a USA TODAY analysis of federal data shows.

Though the law is projected to raise more than $800 billion in taxes, fees and penalties over a decade, 40% comes from about 3.5 million households with adjusted gross incomes above $200,000. Employers, insurers and health care providers are slated to fork over much of the rest.

Republicans insist much of the tax burden will get passed along to middle-income taxpayers. Sen. Orrin Hatch, R-Utah, top Republican on the Senate Finance Committee, notes one in 10 of those taxed for failing to buy health insurance will be below the federal poverty level.

"Twelve of the 21 taxes in the Democrats' health care law will hit middle-class families," says House Ways and Means Committee Chairman Dave Camp, R-Mich. "That's a double-hit on both families and job creators already struggling with the high cost of health care."

On the other hand, about 18 million people will get tax credits if they buy health insurance plans through new federal or state exchanges.

"The Affordable Care Act is the largest health care tax cut in history," says Jason Furman, deputy director of the White House National Economic Council. "It will provide a significant net tax cut for middle-class families and the millions of Americans who will seek affordable insurance in the years ahead."